Telephone system



Feb. 18, 1941. w, McCLEW r 2,232,181

TELEPHONE SYSTEM Filed Dec. 27, 1937 2 Sheets-Sheet 1 Pg LP flmin, gmzzm m iZ @6722 744244515 Feb. 18, 1941. w, McCLEW ET-Al, 2,232,181

TELEPHONE SYSTEM Filed Dec. 'r, 1957 2 Sheets-Sheet 2 $300 M5 I 2' g).

T0 INCOMING SELECIUR- 3 CZAQWT (GI/a169 djgneyl Patented Feb. 18, 1941TELEPHONE SYSTEM John William McClew and Austin Hugh Williams,Liverpool, England, assignors to Associated Telephone & TelegraphCompany, Chicago, 111., a corporation of Delaware Application December27, 1937, Serial No. 181,938 In Great Britain January 6, 1937 11 Claims.

The present invention relates to telephone systems and is moreparticularly concerned with systems employing impulse repeaters of thetype adapted to receive a train of distorted impulses on a registeringdevice and to retransmit them to a succeeding switch in corrected formas regards both ratio and speed.

Arrangements have already been suggested for use in conjunction withsuch impulse repeaters whereby the calling party is charged inaccordance with the duration of conversation. This time-metering featurehas however usually necessitated the provision of a rotary step-by-stepswitch individual to each repeater, which on the reply of the wantedparty is advanced under the control of common time pulse equipment inorder to measure the predetermined conversational period allowedfor eachfee payable by or charged to the calling party. The chief object of theinvention is to provide an improved arrangement whereby the impulseregenerating and conversation timing functions may be performed by thesame piece of equipment so that an important economy-in the use ofapparatus is realised.

The invention may be carried out with particular advantage by the use ofa so-called mechani-' cal impulse repeater of the type disclosed in J.W. McClew and C. R. Woodlands application No. 79,830, filed May 15,1936, now Patent No. 2,188,461, dated Aug. 16, 1938.

According to one feature of the invention in a telephone systememploying register senders in association with outgoing trunk linesregistering equipment responsive to trains of incoming impulses isadapted to be operated after the desired connection is established tomeasure the duration of the conversation for charging purposes.

According to another feature of the invention in a telephone systememploying a mechanical impulse repeater for the regeneration of impulsesto be transmitted over an outgoing trunk line after the setting impulseshave been transmitted in regenerated form, the equipment is set inoperation to control a metering or like charging operation atpredetermined intervals.

A further feature of the invention is that in a telephone systememploying an impulse regenerator of the type wherein a stepping memberis moved by incoming impulses away from a cooperating member which movestowards the first member to transmit corresponding regenerated impulsesarrangements are provided whereby the first member is stepped at regularintervals away from the second member and after moving a predetermineddistanceproduces circuit changes for controlling a metering or likecharging operation.

The invention will be better understood from the following descriptionof one method of carrying it into effect, reference being had to theaccompanying drawings comprising Figs. 1 and 2 which should be arrangedside by side to form a complete circuit diagram. These figures show thetrunk line equipment, or relay set, which terminates one end of atwo-way junction line and which is taken into use for the extension ofoutgoing calls over the junction line.

In the circuit shown, arrangements are provided for discriminatingbetween outgoing calls originated by regularsubscribers and by coin boxsubscribers so that at the conclusion of each timed period during aconversation, repeat metering takes place in the former case but in thelatter case the conversation is broken down if a further fee is notpaid. Furthermore if the-relay set is seized from a distant exchange,the timing equipment is .not brought into operation since it is clearlynot required as metering is efiected at the originating exchange.

In order that the storage device may perform its dual function, a slightmodification is made to the apparatus described in J. W. McClew and C.R. Woodlands application No. 79,830, filed May 15, 1936, now Patent No.2,188,461, dated Aug. 16, 1938, whereby the oif-normal contacts inaddition to being opened in the normal position, are again opened whenthe receiving disc has been rotated from 37 to steps away from theposition of the sending disc.

Considering now the circuit operation, for the purpose of thedescription a straightforward outgoing call from a regular subscriberwill first be dealt with, in which case the relay set will be seizedover conductors and P. When this occurs the loop extended over cnductors and operates relay A over its outer windings in serieswhereupon relay B is operated over armature al. Relay B thereuponenergises relays IP and BR over armature b2, extends a guard earth atarmature b3 on to the incoming P2 lead associated with incomingselectors, operates relay AL over armature b5 and at armature b6 extendsa guard earth by way of the low resistance lower winding of relay TE onto the P conductor associated with regular and coin box selectors. RelayBR upon operating, at armature br4 applies earth to the common timepulse generation set start lead ST in preparation for the subsequenttiming of conversational periods, while armatures M2 and b4 togethercomplete a loop comprising the windings of relays D and I and theimpulse springs IMP across the outgoing junction in order to prepare theterminating equipment at the distant exchange for the reception ofimpulses. Relay I now operates and polarises the shunt field relay Dover its right-hand winding, the latter however being non-operative inthis condition. Relay AL at armature al3 operates relay BB by way of itslower winding; these relays however have no immediate function.

For convenience, the storage device is indicated diagrammatically in thecircuit by the discs R, P and S and it will be understood from referenceto the details given in the prior specification that the receiving discR is rotated step-by-step in response to the received impulses andcarries with it a marking lever which is released at the end of eachtrain of impulses to push a corresponding pin through the plate P intothe path of the sending disc S. For each digit received, a correspondingpin is pushed through plate P and these serve to regulate the movementof the sending disc S which controls the generation of the outgoingimpulses.

On reception of the first train of impulses, relay A responds and at itsarmature aI repeats the impulses to the receiving magnet RM of thestorage device in parallel with relay C, relays B and C remainingoperated during the train due to their slugs. Relay C upon operating, atarmature cI energises the marking magnet MM of the storage device inorder to tilt the marking lever carried by the disc R clear of the pins.The impulses received by the magnet RM rotate the disc R step by stepand on the first movement of this disc the ofi-normal springs areoperated and at contacts NI various circuits are prepared and an earthis extended to the pin plate P.

At the end of the train of pulses relay A remains steadily operated andon the release of relay C after its slow period the circuit for themarking magnet MM is opened and this magnet restores causing the levercarried by the disc R to release and push a corresponding pin into thepath of the disc S. At the same time the contacts mm controlled by themarking magnet close and complete a circuit for relay ON which thereuponoperates and looks at armature onI for the remainder of the settingoperation to the offnormal contacts NI. Relay ON also completes anoperating circuit for relay AP from earth, offnormal contacts NI, fixedplate P in contact with the pin left projecting after the previous call,the reset pin in the disc S which bears against this pin and thusrestrains this disc from movement, armature on5, contacts sm, winding ofrelay AP to battery, while at armature ant and on! the windings ofrelays D and I are short-circuited, the storage device impulse springsIMP are connected directly in the outgoing loop and the condensers QAand QB are disconnected in order to improve the impulsingcharacteristics of the pulsing-out circuit. On the operation of relayAP, relay IP is disconnected at armature apZ and an energising circuitfor the sending magnet SM is prepared at armature apI. The release timeof relay IP is arranged to be of the order of 600 milli-seconds so thatthe pause between successive trains of impulses which is determinedthereby is ample to allow the selectors in the train being set up tohunt for a free outlet.

When relay IP releases, at armature z'pI the magnet SM is energised,whereupon the pin displaced at the end of the previous call is pushedout of the path of the disc S but owing to the stepped head of the resetpin this disc is not immediately released and remains held until afterthe de-energisation of the magnet SM. Magnet SM at contacts smdisconnects relay AP which thereupon opens the magnet energising circuitand as fully described in the prior specification the sending disc S isnow released and rotates until it comes up against the stop pinindicating the termination of the first train of impulses. During therotation of the disc S the pulses of the first incoming train are sentout in regenerated form by way of the impulsing springs IMP controlledfrom the storage device and these impulses serve to set the distantswitch. Relay AP upon releasing also re-energises relay IP inpreparation for timing the interdigital pause after the sending out ofthe train of pulses. During this time further trains of impulses may bereceived on the receiving disc, the two operations of reception andretransmission being enabled to go on simultaneously but independentlyof each other. When the disc S comes up against the stop pin indicatingthe termination of the first train of pulses, relay AP is again operatedand relay IP released and accordingly the sending magnet again receivesa momentary energisation in order to release the disc S again togenerate the second train of impulses in the manner described.

When all the digits received have been retransmitted, the sending disc Swill catch up with the receiving disc R whereupon the oiT-normalcontacts NI open and prevent further operation of relay AP and relay ONis released thus re-inserting relays D and I in the outgoing loop.

When the called party replies, the battery is reversed in the well-knownmanner on the called side of the circuit and this brings about theoperation of the shunt field relay D which at armature dI operates relayDD. This relay thereupon at armature ddI operates relay DR, at armaturesdd2 and (M3 reverses the current flow over the incoming conductors forsupervision purposes, and at armature dd4 connects earth by way of theright-hand winding of relay DA to the S pulse lead extending to themeter pulse machine, which, it will be understood, is arranged to supplybattery pulses to the S and Z leads with a definite time relation.

On transmission of the next S pulse, relay DA is operated and atarmature daI prepares a. circuit for relay DB which is operated afterthe appropriate time interval from the Z pulse in series with the middlewinding of relay DA. Relay DA remains locked over its left-hand windinguntil relay DB operates from the Z pulse when both the initialenergising circuit and the locking circuit for relay DA are opened, butit remains held over its middle winding in series with the left-handwinding of relay DB for the duration of the Z pulse. During theapplication of this latter pulse relay J is connected by way ofarmatures (i115 and dbZ to the meter pulse lead MP and will be operatedthereover one or more times in accordance with the length of theoutgoing junction. At armature :i I relay J connects booster batteryover common lead II] to the incoming P conductor so as to actuate thesubscribers meter the appropriate number of times. At the end of the Zpulse, relay DA restores to prevent further operation of the meteringrelay J and relay DB remains operated in series with resistance YA toearth over armatures b193, dbl and brI.

Relay DB also at armature db5 connects the receiving magnet RM of thestorage device to the common lead I2 to which an earth pulse of shortduration is connected from the time pulse generation set every four anda half seconds. On reception of the next pulse the magnet RM will beenergised in parallel with relay whereupon at armature cl the markingmagnet MM will also be energised. At the conclusion of this pulse themagnet RM will be de-energised and since it is of the reverse drivetype, the receiving disc R will now be rotated one step. The regeneratoroff-normal springs will now be operated and at contacts NI complete acircuit for relay ON by way of armature d1'3 since the marking magnetinterrupter contacts mm will still be open. On release of relay 0 afterits slow release period the energising circuit for the marking magnetwill be opened but it remains energised by the reduced current flowingover armatures drd and t3 and resistance YB. On the next and subsequentpulses the magnet RM only will respond since the energising circuit ofrelay C is now disconnected at armatures 0M and M2. The disc R of theregenerator will thus be rotated step by step in order to measure thepredetermined conversational period allowable for the first meter fee.

Just prior to the end of this period which is of the order of threeminutes duration, it is arranged that an audible. signal is transmittedto the calling party to inform him that he must conclude hisconversation or otherwise he will be charged for a further period. Forthis purpose it is arranged that after the receiving disc R has beenrotated 37.steps away from the sending disc (which is still restrainedby the pin displaced at the end of the last dialled'digit) theoil-normal springs are again opened thus removing the short-circuit fromrelay T. This relay noW operates in series with relays ON and AP inparallel over a circuit including armatures dbl-i and 0M, relays ON andAP holding operated in this condition. Relay T at armature t2disconnects the irnpulsing circuit to the receiving magnet RM and atarmature t3 opens the holding circuit for the marking magnet whereuponthe lever carried by the receiving disc R is allowed to tilt backtowards the plate P and thus moves the pin opposite which it ispositioned into the path of the sending disc S. This serves to provide ahoming position to which the sending disc S will be subsequently rotatedon restoration of the device to normal, either in preparation for timinga further periodor for dealing with a further call. Relay T also atarmature tl connects the right-hand winding of relay CD to the commonlead M from the time pulse generation equipment to which an earth pulseis connected every 12 seconds. On reception of the next pulse, relay CDis energised over its right-hand winding which is only efficient enoughto close the make-first armature cdl. At the end of the pulse the earthshunt is removed. from the left-hand efficient winding of relay CD andit now operates fully by way of its two windings in series overarmatures ed! and dbfi. Lead [4 is now extended over armature cd2 torelay CO which is also of the two-step type and the sending magnet SM isnow energised over armatures ipl, apl and cd3 and opens the holdingcircuit of relay AP at contacts sm. Relay AP upon releasing disconnectsthe sending magnet energising circuit whereupon the sending disc isfreed in the normal manner and rotates until it catches up with thereceiving disc as marked by the pin displaced on operation of relay T.During this rotation of the disc S the impulse springs IMP finding acircuit from the earthed transformer connected to common lead ll,through condenser QC to earth via the middle winding of relay A. Thenceit is transmitted by induction to the outer windings of this relay andis thus extended on to the incoming negative and positive conductors ina balanced circuit. The calling party must now decide during thefollowing grace. period whether he will conclude the conversation or bemetered for a further period.

At the end of a further 12 seconds interval relay CO is operated fromlead M in a similar manner to relay CD and on operation of this relaythe pip-pip tone circuit is disconnected at armature 003. Arrangementsare provided whereby repeat metering may at once take place or the graceperiod may be extended for a further 12 seconds. If terminals l5 and I!are strapped, on the operation of relay CO earth will be extended by wayof armature 004 to short-circuit and release relay DB which has hithertobeen holding over its right-hand winding in series with resistance YAwhile if terminals l5 and G8 are strapped, relay DB will not be releaseduntil the reception of the next earth pulse over lead I4. If, on releaseof relay DB, the calling party has not already hung up, metering againtakes place on the next Z pulse and the timing of the secondconversational period is commenced. The release of relay DB releasesrelays CD and CO and when relay DB re-operates pulses from lead l2 areagain connected to the receivingmagnet RM.

At the end of the conversation when the calling party restores hisreceiver, it will first be assumed that the timing device is part waythrough the measurement of a period. On release of relay A, relay 3commences to release and during its release time. relay C is operatedwhilst relays AL, BB, BR, DD, AP, ON, DB, D and I and also the markingmagnet MM are already operated. On release of relay B, the forward loopis opened to release the switches in the distant exchange, whereuponrelays D, I and DD release so that the pulsing circuit to the magnet RMis opened at armature ddfi whilst relays BR and C which are slow inreleasing due to their slugs now commence to release. During thereleasing time of relay BR, the guard earth is removed from the incomingP and P2 leads thereby enabling the preceding train of switches to bereleased for further use with a minimum of delay and on release of thisrelay the guard earth is replaced until relay BB is released when thestorage device is subsequently restored to normal. On release of relayCthe holding circuit for relay DR is opened and on release of the latterafter its slow period the sending magnet SM receives a momentaryenergisation by interaction with relay AP. Thereupon the sending disc Sis freed and at the same time the marking magnet is de-energised anddepresses a pin to provide a home position to which'the sending discwill rotate. The release of relay AP by the operation of the sendingmagnet SM releases relays DB and AL, but relay BB remains held from theoperated armature 0113. When the sending disc S catches up to thereceiving disc R, relay ON restores due to the opening of the off-normalcontacts NI and opens the latter the relay set is completely restoredand is available for further use.

Should the calling party hang up during the grace period after receiptof the warning tone, relay CD will be operated in addition to the relayspreviously mentioned and the sending disc will already be released andwill be rotating to catch up with the receiving disc. The circuitoperation on release of relay B will however follow a similar course tothat just described.

In case the calling party should hang up just before the commencement ofmeasurement of a further period, in which case relays ON, AP and DB willbe normal, the releasing and guarding operations take place in thefollowing manner. During the release time of relay B, relay C isenergised in parallel with the receiving magnet RM and hence the markingmagnet MM is also energised. On release of relay B, the magnet RM isde-energised and the disc R is thereupon rotated one step due to thereverse drive principle of the magnet armature Whilst on the subsequentrelease of relay C the marking magnet is released to displace acorresponding pin in the disc P. Relay ON is operated on the closure ofthe off-normal contacts NI and operates relay AP; the release thereupontakes place in the normal manner.

In case the subscriber should release the connection prematurely, thatis, by hanging up his receiver during dialling, any digits stored in thestorage device are sent out into an open circuit, while it will benoticed that since relay IP cannot be operated on each release of relayAP during the homing since relay B is normal, there will be nounnecessary pause between the transmission of each digit. The relay setwill be thus freed for further use with a minimum of delay.

Assuming now that an outgoing call is originated by a coin boxsubscriber, it will be routed to the relay set by way of a special coinbox selector having access to the same, +and P conductors as were usedin the connection just described. On the operation of relay B theincoming P conductor will be guarded over armature b6, low resistancelower Winding of relay TE and armature 03:15 as before. In this casehowever, a momentary battery pulse is' now applied to the P lead fromthe coin box selector whereupon relay TE is operated and at armature te2operates relay CB which locks at armature chi and completes a lockingcircuit for relay TE over its upper winding. The circuit operation nowproceeds in the normal manner up to the point where the pip-pip warningtone is extended to the calling party, who 'has now to decide whether toconclude his conversation or to pay another fee. Relay TG will now beoperated over its lower winding in series with the earthed tonetransformer by way of armatures c124, odd and co3 and looks over itsupper winding by way of armatures cb'3, tel and 1591, relay TE havingbeen released by the operation of relay DA at the beginning of thetiming cycle. Relay TG at armature 02 makes the holding circuit forrelay A dependent on the earth supplied by armatures (H94 and bb l andhence it will be appreciated that relay TG must be restored to normalbefore relay DB is released at the end of the grace period, otherwiserelay A will be released and the conversation in progress will be brokendown. If the calling coin box subscriber inserts the necessary feeduring this time, a momentary battery pulse is again supplied over theincoming P lead from the coin box selector whereupon relay TE will beoperated and will lock up as before, while on the operation of relay COrelay TG will be released to maintain the earth feed to relay A.Conversation may now proceed for a further predetermined period withoutfurther payment.

It will be seen that if terminal I! is strapped to terminal 16 ratherthan to terminal l5, the effect would be that a regular subscriber couldhave a call of unlimited length for the initial fee while a coin boxsubscriber would have to make an additional payment at the end of eachpredetermined period. A convenient arrangement in practice would be tostrap terminals I5 and I1 and IE and I8 and connect armature 04 to earthover a normally closed armature of relay CB. This would mean that bothclasses of subscribers would be charged on a time basis but the coin boxsubscriber would be allowed an extra 12 seconds grace period which Wouldgive him an opportunity to find and insert further coins.

Should the relay set be seized from an incoming selector terminating ajunction from a distant exchange, seizure will take place over theincoming-, +and P2 leads. On operation of the incoming selectorswitching relay, the guard earth normally extended forward during therelease time of the B relay therein operates relay J over its left-handwinding while relays A and B in the relay set are operated in the usualmanner. On the operation of relay B a guard earth is supplied fromarmature 113 to the P2 conductor, this earth holding relay J by way ofarmatures da3 and 7'4. At armature 73 the initial energising circuit forrelay DA is disconnected and thus when the called party replies andrelays D and DD are operated in the normal manher, there will be nocircuit to operate relay DA and start up the timing cycle. Thisarrangement is provided since the bringing into operation of the timingmechanism is not required and would involve unnecessary wear and tear,whilst the connection of the pip-pip tone to the line would interferewith the conversation.

In order to'efiect junction economy it is arranged in the circuit shownthat if the relay set is seized over the conductors and +l, the incomingswitch in the distant exchange will be caused to switch over to a secondset of Wipers and thus in response to the same received digits willroute the call to a different destination. On seizure of the relay set,relay LD will be operated over its left-hand winding in series withrelay A which also operates and on operation of relay BB in the normalmanner relay LD looks over its right-hand winding to earth via armaturesZdl, c2 and b174, while its left-hand winding is short-circuited atarmature 12125 to prevent the inductance of this winding frominterfering with the impulsing circuit to relay A. Relay LD uponoperating connects earth at armature 1:22 and M3 to the outgoingnegative and positive junction conductors in order to bring about theoperation of a differential relay in the distant incoming selector,which relay thereupon locks and causes the switching over to the secondset of wipers. On reception of the first set of dialled impulses, themagnet RM responds in the normal manner and relay C at armature c2 opensthe holding circuit of relay LD which thereupon releases and the circuitoperation thereafter proceeds in the normal manner.

In case the storage device fails to function correctly in either of itstwo capacities, a delayed alarm will be brought into operation andtherelay set will be busied out. The supervision is arranged to cover theoperating circuits for the receiving, marking and sending magnets, theoff-normal contacts and the operating path for relay AP and in case thedevice cannot be stepped off-normal or be restored to normal after asetting operation due to either a disconnection in any of these circuitsor to a mechanical fault, alarm conditions will be brought about.

For example, if the mechanism fails to send out its stored pulses,relays ON and AP remain operated. On release of relay B when the callingparty subsequently hangs up in order to re-dial, relay BB will bemaintained from armature on3 and will guard the relay set againstseizure by further outgoing calls, whilst earth will be extended overarmatures brl and 0118 to light the supervisory lamp LP in series withdelayed alarm equipment connected to common lead l3. Should themechanism fail to home from any of the positions 37! to 4i], on releaseof relay B since relay ON is already normal due to the open condition ofthe off-normal contacts NI, relay AL will hold operated and willmaintain relay BB for guarding purposes and the delayed alarm will bebrought into operation by way of armature 1112. A similar result wouldoccur if the receiving disc R. could not be rotated due to somemechanical or electrical fault,

Considering now an incoming call over the bothway junction, on seizureof the incoming selector the guard earth connected to the P leadoperates relay BB over its upper winding and this relay thereupon guardsthe relay set and hence the junction from seizure by an outgoing call.

The test terminals marked TJ giving access to various controlling pointsof the circuit are provided for the convenience of the exchangemaintenance staff.

The high resistances connected across conductors QA and QB in thetransmission circuit serve to eliminate microphonic noise whilst thecondensers and associated resistances connected in parallel with thevarious impulsing circuits prevent destructive arcing at the contacts.

From the foregoing description it will be appreciated that in exchangeareas where time metering is required on junction calls, the applicationof the invention enables the advantages of impulse regeneration to behad without further cost whilst in areas where both time metering andimpulse regeneration are required the invention provides an efficientand economical solution.

We claim:

1. In a telephone system in which calls are extended by automaticswitches, a step-by-step device operated by impulses from a callingstation and effective to directively control said switches to extend acall in accordance with said impulses, and means for operating saiddevice at spaced intervals during the talking period of said call.

2. In a telephone system wherein calls are extended over automaticswitches, a step-by-step device operated by impulses from a callingstation and effective to directively control said switches to extend acall, means effective after the call has been extended for transmittingan impulse to said device at spaced intervals, and means controlled bysaid device and rendered effective periodically throughout theconversation for transmitting an audible tone to the conversingsubscribers.

3. In a telephone system wherein calls are extended over automaticswitches, impulse operated means for directively controlling saidswitches to extend a connection, means effective after the connection iscompleted for again operating said first means by impulses, meanscontrolled by said first means and operated periodically to impress anaudible tone upon the connection after the connection is completed,means operated an interval of time after each operation of said lastmeans, and means for varying said interval of time.

4. A telephone system as claimed in claim 3 having subscribers lines ofdifferent classes, wherein said last means varies said interval of timeautomatically in dependence upon the class of the calling line.

5. In a telephone system, a device for timing conversations comprising,a member rotatable in but one direction and having no normal position,means for arbitrarily marking any position occupied by said member as anindex position, and impulse responsive means operated periodicallyduring a conversation thereby to rotate said member in steps from saidindex position, and means controlled by said device for causing theconversation to be interrupted responsive to rotation of said member apredetermined number of steps from said index position.

6. A timing device for use in telephone systems comprising, a memberrotatable in but one direction and having no normal position, means forarbitrarily marking any position occupied by said member as an indexposition, impulse responsive means operated periodically to rotate saidmember in steps from said index position, and means operated responsiveto rotation of said member a predetermined number of steps from saidindex position.

'7. A timing device for use in telephone systems comprising, a pair ofmovable members normally occupying adjacent positions, impulseresponsive means operated periodically for moving one of said members insteps away from the other member, means operated responsive to theseparation of said two members by a predetermined number of steps, andmeans controlled by said last means for moving said other member to aposition adjacent the position then occupied by said first member. I

8. A timing device for use in telephone systems comprising, a movablemember, means for marking the position occupied by said member, meansfor effacing the marking of a position previously occupied by saidmember, impulse responsive means operated periodically to step saidmember in a particular direction, and means effective responsive to saidmember being moved a predetermined number of steps from the last markedposition occupied by said member for controlling said first means andsaid second means to cause the position then occupied by said member tobe marked and to cause the marking of said last marked position to beefiaced.

9. In a measured service telephone system, an impulse repeater havingtwo stepping members normally occupying adjacent positions wherein thefirst member moves away from the second member responsive to receivedimpulses and the second member moves toward the first member to transmitcorresponding impulses during the extension of a call, a meteringcircuit, and means for rendering said circuit effective after said callafter the call is extended thereby to step said first member away fromsaid second member, and means operated responsive to the separation ofsaid members by a predetermined number of steps.

10. In a measured service telephone system wherein calls are extendedover automatic switches, an impulse repeater having one member movedresponsive to impulses from a calling station and a second member movedover the same path as said first member for controlling the transmissionof corresponding impulses to said switches to extend a call, means formoving said first member during the talking period of said call, andmeans for transmitting metering impulses in accordance with the movementof said first member during said talking period.

11. A timing device for use in telephone systems, comprising, a seriesof elements each havinga normal position, a movable member operativelyassociated with one of said elements, means for displacing said oneelement, means for moving said member step-by-step to operativelyassociate said member with others of said elements in sequence, andmeans operated responsive to said member being moved a predeterminednumber of steps from said one element for causing said first means todisplace that element with which said member is then operativelyassociated.

JOHN WILLIAM McCLEW. AUSTIN HUGH WILLIAMS.

